Development of an empirical model for chlorophyll-a and Secchi Disk Depth estimation for a Pampean shallow lake (Argentina)

Shallow Pampean lakes are located in the most productive plain of Argentina. They are highly variable in salinity, turbidity and surface area. Laguna Chascomús has been monitored as a representative example of them. We developed a linear model based on satellite images validated against field measurements (2001–2011 period). A vegetation index and Landsat Surface Reflectance (Band 4) produced the best correlations with chlorophyll-a (Chl-a) and Secchi Disk Depth (SDD), respectively. In a second instance, a retrospective analysis (1986–2013) was performed. As a result, significant positive trends were observed for SDD and Chl-a. In addition, both variables displayed trends related to rainfall and site depth.Fil: Bohn, Vanesa Yael. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca; Argentina. Universidad Nacional del Sur. Departamento de Geografía y Turismo; ArgentinaFil: Carmona, Facundo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional del Centro de la Provincia de Buenos Aires. Rectorado. Instituto de Hidrología de Llanuras - Sede Tandil. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto de Hidrología de Llanuras - Sede Tandil; ArgentinaFil: Rivas, Raúl Eduardo. Universidad Nacional del Centro de la Provincia de Buenos Aires. Rectorado. Instituto de Hidrología de Llanuras - Sede Tandil. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto de Hidrología de Llanuras - Sede Tandil; ArgentinaFil: Lagomarsino, Leonardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús). Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús); ArgentinaFil: Diovisalvi, Nadia Rosalia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús). Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús); ArgentinaFil: Zagarese, Horacio Ernesto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús). Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús); Argentin

Cytosolic Crowding Drives the Dynamics of Both Genome and Cytosol in Escherichia coli Challenged with Sub-lethal Antibiotic Treatments.

In contrast to their molecular mode of action, the system-level effect of antibiotics on cells is only beginning to be quantified. Molecular crowding is expected to be a relevant global regulator, which we explore here through the dynamic response phenotypes in Escherichia coli, at single-cell resolution, under sub-lethal regimes of different classes of clinically relevant antibiotics, acting at very different levels in the cell. We measure chromosomal mobility through tracking of fast (<15 s timescale) fluctuations of fluorescently tagged chromosomal loci, and we probe the fluidity of the cytoplasm by tracking cytosolic aggregates. Measuring cellular density, we show how the overall levels of macromolecular crowding affect both quantities, regardless of antibiotic-specific effects. The dominant trend is a strong correlation between the effects in different parts of the chromosome and between the chromosome and cytosol, supporting the concept of an overall global role of molecular crowding in cellular physiology.UKRI grant EP/T002778/

Divergent dynamics of microbial components in two temperate shallow lakes with contrasting steady states in the Southern Hemisphere

Factors that affect abundances of organisms in water bodies are influenced by extrinsic and intrinsic drivers that operate from outside and within a system. A high temporal coherence in the dynamics of abiotic parameters and biological communities among neighboring lakes evidences a strong extrinsic control operating similarly across lakes, and allows for prediction of ecosystems evolution in the context of global change and intensive land use. The Pampa region (Argentina) encompasses many shallow lakes submitted to different degrees of anthropic influence and showing contrasting alternative states. We studied an eutrophic clear and a hypertrophic turbid shallow lake during an annual cycle in order to evaluate whether they responded similarly to extrinsic factors or these were overridden by the effects of the steady state of each lake. Physical and chemical variables were highly coherent between both lakes, but accounted little for the large disparities among abundances and dynamics of microorganisms. While communities from the clear lake responded to a combination of extrinsic and intrinsic factors, the turbid lake showed a state less prone to be affected by climatic effects. We hypothesize that clear lakes would perform better as sentinels of climate change in the Pampa wetland.Fil: Fermani, Paulina. Universidad Nacional de San Martin. Instituto Tecnologico de Chascomus. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - la Plata. Instituto Tecnologico de Chascomus.; ArgentinaFil: Lagomarsino, Leonardo. Universidad Nacional de San Martin. Instituto Tecnologico de Chascomus. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - la Plata. Instituto Tecnologico de Chascomus.; ArgentinaFil: Torremorell, Ana María. Universidad Nacional de San Martin. Instituto Tecnologico de Chascomus. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - la Plata. Instituto Tecnologico de Chascomus.; Argentina. Universidad Nacional de Luján; ArgentinaFil: Escaray, Roberto Ulises. Universidad Nacional de San Martin. Instituto Tecnologico de Chascomus. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - la Plata. Instituto Tecnologico de Chascomus.; ArgentinaFil: Bustingorry, Jose Fernando. Universidad Nacional de San Martin. Instituto Tecnologico de Chascomus. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - la Plata. Instituto Tecnologico de Chascomus.; ArgentinaFil: Llames, Maria Eugenia del Rosario. Universidad Nacional de San Martin. Instituto Tecnologico de Chascomus. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - la Plata. Instituto Tecnologico de Chascomus.; ArgentinaFil: Pérez, Gonzalo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; ArgentinaFil: Zagarese, Horacio Ernesto. Universidad Nacional de San Martin. Instituto Tecnologico de Chascomus. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - la Plata. Instituto Tecnologico de Chascomus.; ArgentinaFil: Mataloni, Maria Gabriela. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental. - Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigación e Ingeniería Ambiental; Argentin

Chascomús : structure and functioning of a turbid pampean shallow lake

La laguna Chascomús es un típico lago somero, eutrófico y turbio de la Pampa Deprimida. Se encuentra permanentemente mezclada y presenta un grado elevado de homogeneidad espacial. La alternancia entre períodos de déficit y de exceso de agua, característica de la región, determina que la laguna sufra ciclos periódicos de sequía e inundación. Las primeras crónicas indican que a principios del siglo XX la laguna era turbia y que las primeras matas de vegetación habrían aparecido después de las inundaciones de 1913 y 1914. Hacia mediados del siglo XX, Chascomús se encontraba en un estado de aguas claras y colonizada de manera profusa por macrófitas. En ese momento, aproximadamente 60% de la biomasa de peces correspondía al pejerrey (Odontesthes bonariensis). En las últimas décadas, esta condición se modificó y en la actualidad la laguna está estabilizada en un estado turbio en el que la producción primaria fitoplanctónica es muy alta y se encuentra limitada por luz. La biomasa de fitoplancton representa el 75% del carbono de la columna de agua y predominan las cianobacterias nanoplanctónicas. Estudios de campo y experimentos en mesocosmos indican que la transparencia del agua está controlada por la cantidad de radiación incidente a través de una retroalimentación negativa con la producción primaria. La biomasa fitoplanctónica elevada se mantiene debido a la ausencia de un control efectivo por parte del zooplancton herbívoro. Como resultado de la presión de depredación que ejerce la comunidad actual de peces, la composición del zooplancton no presenta filtradores eficientes (e.g., Daphnia y otros cladóceros de gran tamaño). En la actualidad el pejerrey representa un porcentaje muy bajo de la biomasa total de peces (0.04%), mientras que los micrófagos omnívoros, como el sabalito (Cyphocharax voga), son dominantes. La dominancia del sabalito no sólo explicaría la baja abundancia del zooplancton, sino que al mismo tiempo contribuiría a evitar o retardar la consolidación del material sedimentado.Laguna Chascomús is an eutrophic, turbid, shallow lake typical of the Flooding Pampa region of Argentina. This shallow lake is permanently mixed and displays a high degree of spatial homogeneity. The cyclical periods of excess and shortage of rain, characteristic of this area, result in periodic drying and flooding events. According to newspaper articles published during the first half of the XX century, the lake was originally turbid. The first patches of rooted vegetation appeared after the 1913 y 1914 floods. During most part of the XX century the lake remained in a “clear”, vegetated state. During this period the dominant fish species was the silverside (pejerrey), Odontesthes bonariensis, which accounted for over 60% of the total fish catches (in biomass). Instead, by the end of the latest century the lake shifted to a turbid state that persisted until present. Currently, the phytoplankton primary production is limited by light and its values are among the highest ones reported for natural aquatic systems. In light limited systems, the transparency may be expected to be controlled by the amount of incident light, through a negative feedback loop with primary production. These predictions have been confirmed, both in mesocosm experiments and “in situ”. The phytoplankton biomass, dominated by nanoplanktonic cyanobacteria accounts for 75% of the total amount of carbon in the water column. The equilibrium predicted by the light limitation theory could not hold if the model assumptions were violated. This situation could happen if the phytoplankton biomass were controlled by herbivore zooplankton. However, such a control of primary producer by herbivores seems to be precluded due to the absence of large-sized zooplankton grazers, presumably due to the composition of the fish assemblage. In contrast to earlier reports of the 1960, the proportion of pejerrey biomass is presently quite low (0.04%), while presently the community is dominated by omnivore microphagous, such as the sabalito (Cyphocharax voga). The dominance of sabalito could not only explain the composition of the zooplankton community, but it also could contribute to prevent or delay the consolidation of sediments

Optical properties of highly turbid shallow lakes with contrasting turbidity origins: The ecological and water management implications

A comprehensive optical study of three highly turbid shallow lakes was presented. The lakes contained very high concentrations of optically active substances [OASs] with clear differences in total suspended solid [TSS] composition among them. Lakes presented elevated values of total absorption [at()] and scattering coefficients [b()], which translated into extremely high light attenuation coefficients [Kd(PAR)]. Differences among lakes in the estimation of Kd(PAR), using two typical estimators of light penetration (i.e., nephelometric turbidity [Tn] and Secchi disk [ZSD]), were analysed. Kirk´s optical model was used to model Kd(PAR) using inherent optical properties [IOPs]. Modelled values of Kd(PAR) agreed very well with those measured (R2 = 0.95). In addition, optical properties and Kirk´s model were used to determine water quality targets for restoring submerged aquatic vegetation [SAV]. Based on a minimum light requirement for SAV of 10%, results showed that only an integrative remediation action, considering substantial reduction of TSS and Chl a (95%), and CDOM (50%), must be contemplated to improve maximum colonization depth for SAV to values higher than 0.7 m. On the other hand, phytoplankton absorptive characteristics were also studied. In these lakes, phytoplankton showed different responses to the nature of light competition. Some of the variation in specific phytoplankton absorption [a*ph()] was explained by differences in the ratio between unpigmented particulate absorption and phytoplankton absorption (up to R2 = 0.48 for the blue band). Hydrologic optical results were discussed in terms of ecological and management implications.Fil: Pérez, Gonzalo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones En Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Reg.universidad Bariloche. Instituto de Investigaciones En Biodiversidad y Medioambiente; ArgentinaFil: Lagomarsino, Leonardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús). Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús); ArgentinaFil: Zagarese, Horacio Ernesto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús). Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús); Argentin

¿Qué son "los nutrientes" en los ecosistemas acuàticos ?

Como su nombre lo indica, los nutrientes son compuestos químicos que resultanesenciales para el crecimiento y desarrollo de las algas, y de las plantas presentesen los cuerpos de agua. Si bien existen una amplia variedad de nutrientes, en generalse considera a aquellos compuestos de Nitrógeno (N) y de Fósforo (P) como los másimportantes, siendo también representativos de las condiciones de calidad de losecosistemas acuáticos.Fil: Lagomarsino, Leonardo. Universidad Nacional de San Martin. Instituto Tecnologico de Chascomus. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - la Plata. Instituto Tecnologico de Chascomus.; ArgentinaFil: Bustingorry, Jose Fernando. Universidad Nacional de San Martin. Instituto Tecnologico de Chascomus. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - la Plata. Instituto Tecnologico de Chascomus.; ArgentinaFil: Escaray, Roberto Ulises. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas; Argentin

Changes in the phytoplankton structure in a Pampean shallow lake in the transition from a clear to a turbid regime

We analysed the changes in phytoplankton and in the main limnological features in a shallow lake during its transition from a clear-vegetated regime to a turbid one from 2005 to 2013. As samplings were discontinuous, data were analysed considering three different sampling periods. At the beginning of the first period, the lake was in a clear-vegetated regime, showing low values of chlorophyll a, KdPAR, total suspended solids and nutrients, and high Secchi depth. Phytoplankton was dominated by nano-phytoplanktonic species. During the second period, some evidences of the shift to a turbid regime were observed (mainly in KdPAR and total suspended solids). Towards the end of our study, submerged macrophytes sharply declined; in this period KdPAR and total suspended solids noticeably increased, whereas a significant reduction in Secchi depth occurred. Concomitantly, phytoplankton abundance augmented in two orders of magnitude, changing to a community with a higher proportion of micro phytoplankton. Although the causes of the regimen shift could not be unequivocally assessed, the drastic reduction in the hydrometric level of the lake probably provoked a declination in macrophytes, with the consequent increase of nutrients in the water column and the increment in phytoplankton densities, carrying the system towards a turbid regimeFil: Sánchez, María Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; ArgentinaFil: Lagomarsino, Leonardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas ; ArgentinaFil: Allende, Luz. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; ArgentinaFil: Izaguirre, Irina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; Argentin

Seasonal patterns and responses to an extreme climate event of rotifers community in a shallow eutrophic Pampean lake

Shallow lakes of temperate areas experience seasonal and inter-annual variability in weather conditions, impacting on their biological communities. Here, we studied the temporal fluctuation of the zooplankton community in a highly eutrophic shallow lake, Laguna Chascomús. Rotifers and the cyclopoid copepod Acanthocyclops robustus dominated the community. The most important rotifers were Brachionus caudatus, B. havanaensis, and Keratella tropica. The abundance of the two Brachionus species reached maximum values in late summer/early autumn. In contrast, K. tropica and A. robustus did not display seasonal patterns. A prolonged period of low water temperature resulted in a massive fish winterkill event (in 2007), which seemingly allowed the development of unusually dense populations of cladocerans. We used vector autoregressive models to analyze the rotifer time series. The model accounted for 76% of the variance in rotifer abundance and provided evidence of their dependence on temperature and chlorophyll a. In addition, the impact of the fish winterkill on rotifer abundance could be assessed through intervention analysis. The evidence collected here suggests that the zooplankton community structure is controlled by fish planktivory, while rotifers population dynamics are mostly driven by temperature and available food. Both processes seem highly responsive to forcing weather variables.Fil: Diovisalvi, Nadia Rosalia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús). Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús); ArgentinaFil: Salcedo Echeverry, G.. Universidad del Quindío; ColombiaFil: Lagomarsino, Leonardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús). Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús); ArgentinaFil: Zagarese, Horacio Ernesto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús). Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús); Argentin

Seasonal Variability of Optical Properties in a Highly Turbid Lake (Laguna Chascomús, Argentina)

We study the underwater light field seasonality in a turbid lake, Laguna Chascomús (Buenos Aires, Argentina). We report (1) relationships between optical properties (OPs) and optically active substances (OASs); (2) relationships between inherent (IOPs) and apparent (AOPs) optical properties; and (3) the seasonal variability in OASs and OPs. Light absorption was dominated by the particulate fraction. The contributions of phytoplankton pigments and unpigmented components were similar. The best predictors of total particulate absorption, unpigmented particulate absorption, turbidity and vertical attenuation coefficient were total suspended solids or their ash content. Many OASs and OPs varied seasonally. The concentrations of OASs were higher during spring and summer, resulting in lower transparency and higher turbidity. However, mass‐specific absorption coefficients displayed lower values during spring and summer. Thus, the higher light attenuation observed during spring and summer resulted from higher concentrations of relatively less absorptive OASs. Collectively, these results suggest that: (1) light extinction is enhanced during spring and summer; (2) the enhanced light extinction is due to changes in the particulate fraction; (3) the enhanced light extinction is mostly due to an increase in the amount of particulate material; and (4) the increase of particulate matter also enhanced light extinction through increased scattering.Fil: Pérez, Gonzalo Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas; ArgentinaFil: Llames, Maria Eugenia del Rosario. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas; ArgentinaFil: Lagomarsino, Leonardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas; ArgentinaFil: Zagarese, Horacio Ernesto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas; Argentin

Diel patterns of total suspended solids, turbidity, and water transparency in a highly turbid, shallow lake (Laguna Chascomús, Argentina)

The effects of external physical forcing variables (solar radiation and winds) on short-term dynamics of total suspended solids (TSS), Chlorophyll- a (Chl-a), turbidity levels, and water transparency were studied during 15 days in a highly turbid, shallow lake (Laguna Chascomu´ s, Argentina). Water samples were taken three times per day (8, 14 and 20 h.). Solar radiation and wind velocity showed a repeatedly bell-shaped diurnal pattern, with significant higher values during morning and afternoon, respectively.TSS and turbidity displayed a general decreasing trend during the sampling period, while water transparency showed the opposite trend. Also Chla displayed a decreasing trend and was closely correlated to TSS levels. We assayed a first-order kinetics model to detrend the series, obtaining the rate of change during the night, morning, and afternoon. We observed higher values on afternoon compared to morning for TSS, Chl-a, and turbidity levels and the opposite pattern for water transparency. We conclude that this pattern may result from a combination of biological activity, as it took place after a period of intense photosynthetic activity, together with resuspension by winds during the afternoon, (windiest time of the day).Fil: Lagomarsino, Leonardo. Instituto de Investigaciones Biotecnológicas - Instituto Tecnológico Chascomús (San Martin); Argentina. Universidad Nacional de San Martín; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Diovisalvi, Nadia Rosalia. Instituto de Investigaciones Biotecnológicas - Instituto Tecnológico Chascomús (San Martin); Argentina. Universidad Nacional de San Martín; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Bustingorry, Jose Fernando. Instituto de Investigaciones Biotecnológicas - Instituto Tecnológico Chascomús (San Martin); Argentina. Universidad Nacional de San Martín; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Escaray, Roberto Ulises. Instituto de Investigaciones Biotecnológicas - Instituto Tecnológico Chascomús (San Martin); Argentina. Universidad Nacional de San Martín; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Zagarese, Horacio Ernesto. Instituto de Investigaciones Biotecnológicas - Instituto Tecnológico Chascomús (San Martin); Argentina. Universidad Nacional de San Martín; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin